Attraction of Aphidius ervi (Hymenoptera: Braconidae) and Aphidoletes aphidimyza (Diptera: Cecidomyiidae) to Sweet Alyssum and Assessment of Plant Resources Effects on their Fitness

Abstract

The green peach aphid Myzus persicae (Sulzer) (Hemiptera: Aphididae) is one of the most economically important aphid species affecting crops worldwide. Since many natural enemies of this aphid have been recorded, biological control of this pest might be a viable alternative to manage it. Selected plant species in field margins might help to provide the natural enemies with food sources to enhance their fitness. This study aimed to investigate if sweet alyssum, Lobularia maritima (L.) (Brassicaceae), is a potential food source for the parasitoid Aphidius ervi Haliday (Hymenoptera: Braconidae) and the predator Aphidoletes aphidimyza (Rondani) (Diptera: Cecidomyiidae), and whether this flower could contribute to enhance the biological control of M. persicae. Volatiles produced by alyssum, with and without flowers, attracted both natural enemies. This attractiveness to alyssum flowers was disrupted when compared with peach shoots recently infested with a relatively low number of aphids. When aphids were absent, parasitoids exposed to alyssum survived longer than those that fed on a sugar solution or on water. In the case of the predator, alyssum flowers did not benefit longevity since the nectaries were inaccessible to females. However, our results provide evidence that A. aphidimyza would be able to feed on nectar if accessible. The floral resource did not improve the reproductive capacity of the two natural enemies, but the 10% sugar solution increased the egg load of the predator. Provision of other sugar resources, such as flowers with exposed nectaries and extra floral nectar may also be a viable option to improve the biological control of M. persicae.

Alyssum (Lobularia maritima) selectively attracts and enhances the performance of Cotesia vestalis, a parasitoid of Plutella xylostella

“…In the longevity experiments, the three flower species tested increased the lifespan of C. vestalis. This coincides with other studies concerning the impact of buckwheat and alyssum on survival of natural enemies 6,55 . The longevity of C. vestalis females was markedly greater than males in all diet treatments.…”

Optimizing aphid biocontrol with the predator Aphidoletes aphidimyza, based on biology and ecology

“…Adults are not predatory and feed on the honeydew excreted by their aphid prey. Adults can also feed on nectar and this had a beneficial effect on the survival of the adult females . Adults will also feed on honey or sugar solutions, which can be provided to improve adult survival/fecundity (see Section 3.4.3).…”

“…Similarly, provisioning of food (sugar) sources to potentially enhance longevity and/or the egg‐laying potential of the adults in the crop holds promise (Pekas A, unpublished). These include banker plants and artificial provisioning of honeydew or other sugar sources at the site of release or near aphid outbreaks …”

“…Adults can also feed on nectar and this had a beneficial effect on the survival of the adult females. 37 Adults will also feed on honey or sugar solutions, which can be provided to improve adult survival/fecundity (see Section 3.4.3). The mean lifetime fecundity on M. persicae varied considerably among studies: from 70 18 to 156 8 and 250 38 eggs, with a particularly fecund female laying 444 eggs 7 (see Section 2.3.3 for factors affecting egg laying).…”

“…These include banker plants and artificial provisioning of honeydew or other sugar sources at the site of release or near aphid outbreaks. 37,109 It is also necessary to deepen our understanding of how chemicals used in greenhouse production affect the population dynamics of A. aphidimyza; even those considered as 'compatible' by current IOBC standards may cause sublethal or latent effects. 110 The greenhouse environment has also seen rapid technological change in recent years, including the use of LED lights (with different emission spectra/heat signatures to traditional high-pressure sodium lamps), as well as CO 2 supplementation and changes that are likely to come in the face of climate change and in response to the rising cost of heating and cooling.…”